For a 500' run if you are going a pipe size of 1" should be O.K. for just running a sprinkler but how many you run at 1 time may change things. Also your incomeing water pressure will have a factor on the pipe size needed. You may want to consider 1.25" or 1.5"
Are you on a well?
You can find 300' and 500' rolls at any good plumbing supply house. You will still need buried connections where each yard hydrant is and any branch spot.